From December, showroom models will carry information detailing their emission standards, noise levels and fuel consumption figures alongside their price tags, under a voluntary code drawn up by the industry and endorsed by the government.

Potential buyers will be able to compare performance between cars on offer within dealerships which will also be expected to show customers how these rate against other types of car.

The Society of Motor Manufacturers and Traders, which has drawn up the scheme, says it hopes this will make environmental considerations a higher priority for consumers and change advertising priorities by the car giants which pay little attention to them. It has already issued guidance on greener driving, including reducing car use, and is gearing up for plans to link vehicle excise duty and company car taxes to a vehicle's green performance.

Christopher Macgowan, the society's chief executive, forecast that the environmental data would soon become common parlance. "By moving in advance of the changes the industry is providing consumers with the right information well before they need it." Other information, including the percentage of recyclable material in cars, might follow later.